Engine oil grades
 

:confused: Getting ready to change oil and filter for the first time in winter here. This time of year, the temp. can range from 15F to 70F. According to my 1985 owners manual, my choices for this temp. range are:

15w-40
15w-50
20w-40
20w-50
SAE-30
10w-40
10w-50

Any input to help narrow that down some or brand selection would be appreciated.

Thanks,
Mark

Here we go again, another oil thread.:wacko:

Do you want to use synthetic or conventional?

Conventional. I spent about 30 minutes searching for a thread that had an answer that would definitely apply to my situation. I apologize for starting another oil thread since I know there are many. If it is that painful...don't reply.

Mark

i am running 15w40 right now...winter temps range from 5F to 35F...15w40 might be a bit thick for these temps thou....

15W-40 is probably OK for those temperatures. However, if the engine has less then perfect compression or the valves need adjustment or the starter is not perfect, then you will get some starting problems. In such a case, it's time to switch to 10W-40.

Or, switch to synthetic and then you don't need to be as cognizant of the thickness of the oil. You can go 5K on synthetic. It's a bit more costly, but, not significantly, when you take the filter into account.

I just adjusted valves not too long ago, the starter is in good condition but i dont know bout the compression....dont know how to test it..

Don't worry about it. Use the 15W-40 and see how it starts. You might get into trouble below 20°F. but, then again, you might not. A top notch battery and starter will make all the difference.

Before I switched to synthetic, I would run Castrol 15W-40 year round in the W123. It never failed to start, although it really preferred the block heater below 15°F. It almost stranded me in Cincinnati with a bad glow plug. Almost ran out of juice before it finally crawled up to an idle.

I agree 15W40 should be OK for your climate if everything is in good shape. If you do decide to go to synthetic, the Mobil 1 5W40 is impressive in cold temperatures, but expensive (I just paid $5.99/quart locally).

$20.00 for 5 quarts at Wallys.;)

I tried 2 different wallys around here and neither on had it in 5 quart containers, I finally gave up and went to Checker to get the "Truck & SUV" quarts. The first Checker only had 3 quarts in stock, so it still took two trips. What a PITA, but I did both cars so I don't have to worry about it for a little while.

Yep, the availability is spotty up in CT as well. I've purchased it in advance when I find it. It's not worth $6.00 IMHO. But, for $4.00, I'll switch from Rotella syn.

The cars were just starting a little hard with dino when the temperatures got down to +10F or so. I'll keep an eye out at Wallys and grab some for next time.

5k on synthetic
 

is very appealing. However, there is no way I will do 5k in 3 months. I know that 3mo. is a good time to change w/ conventional...Does the same hold true for syn.?

Run 15w-40. I have 15w-40 Delo in the SD now and I notice that until about 20 degrees it is fine. She cranks a little slower but thats ok and I just let it warm for a few minutes. When the temp's drop into the teens or single digits it cranks much slower but still starts.

fyi Walmart 15w-40 diesel oil is like $5 a gallon. :D

I do not plan on switching this car over to synthetic because I plug it in I don't really need it. I'd rather use the $30 that I save to buy a lifter for the SDL.:D

According to Mobil's web site, it looks like they are recommending a maximum 6 months for their synthetics:

http://www.mobiloil.com/USA-English/MotorOil/Car_Care/AskMobil/Recommended_Oil_Change_Intervals.aspx